Sensitization of Escherichia coli cells to oxidative stress by deletion of the rpoH gene, which encodes the heat shock sigma factor

A deletion in the rpoH gene greatly increased the sensitivity of Escherichia coli sodA sodB mutants to oxidative stress. The effect of the rpoH deletion on sodA+ sodB+ cells was only marginal. Mutations in heat shock genes singly sensitized sodA sodB double mutant cells to plumbagin. sodA sodB double mutants were neither more sensitive nor more resistant to thermal stress than the wild type.